DEVELOPMENT OF A PREDICTION MODEL FOR VO2max DETERMINATION IN ADOLESCENT GIRLS

Current practice of determining aerobic capacity (VO2max) of a pediatric population in a clinical setting involves the subject performing treadmill exercise until volitional exhaustion. In many cases, it is difficult to persuade young patients to perform at a maximal level in order to determine their true VO2max. PURPOSE: To develop a prediction model based on a submaximal workload during the Bruce treadmill test to estimate VO2max in adolescent girls. METHODS: Adolescent girls (n = 116, age 13.2 ± 2.0 yr.) performed a maximal Bruce treadmill test. Expired respiratory gases were collected and measured continuously via indirect calorimetry. Heart rate (HR) was also monitored continuously by telemetry. Each subject met two of three criteria: 95% of age predicted HRmax, respiratory exchange ratio > 1.05, and plateau of VO2 (defined by an increase in VO2 of < 2.0 ml·kg−1·min−1 with increasing exercise workload). VO2 and HR at stage one (min 3) and two (min 6) of the Bruce test were entered into a stepwise regression model to predict VO2max. The best model was developed and validated by calculating the predicted error sum of squares (PRESS) statistic. RESULTS: A regression model was developed using VO2 (VO2 min 6) and HR (HR min 6) attained at stage 2 of the Bruce test. The model is shown below. VO2max(ml·kg−1·min−1) = 46.77 - (0.2854155* HR min 6) + (1.46732912* VO2 min 6) The correlation between actual and predicted VO2max was 0.82, with a standard error of estimate = 3.5 ml·kg−1·min−1. Actual average (± SD) VO2max was 36.2 ± 6.9 ml·kg−1·min−1. Predicted VO2max was 36.2 ± 5.5 ml·kg−1·min−1. CONCLUSION: Based on this model, the VO2max of healthy adolescent girls can be predicted within one MET, using submaximal Bruce test data. Using this model during clinical exercise testing will reduce patient anxiety and save time, with little loss of accuracy.